Most of that shadow, it must be said, is from his neck.
But seriously, I get where you are coming from. Whatever shortcomings our player roster has had over the last decade or so, we haven't had to worry about having a quality half. We've certainly had issues with finding him a quality foil/partner, but we've been very lucky to have him. If only for his longevity and the consistency he's brought to the team makeup, he will be missed.
That said, nobody plays forever and change is inevitable. I think the club is doing all they can to develop some sort of succession plan, with Brooks, Jake Arthur, and younger "guns" like Large and Walsh coming through. Whether it will work or not remains to be seen.
Most young halves struggle for consistency at NRL level, no matter how talented they are. Tim Smith, who had 40 assists in his debut season (40!), soon became just another rugby league cautionary tale. One good season does not guarantee a second good season, let alone a decade of excellence. But somewhere along the line - probably not right away - somebody will put up his hand up to become the next great Manly halfback.